Do not create kapp app configmap while using --diff-run (#454)

* not to create configmap while diff-run

* taking care of configmap with suffix

* added e2e test case

* added newline at end of file

* rebased and refactored after prev-app changes

* rebase after final app-suffix changes

* refactored code and renamed test method

* don't update configmap while diff-run

* Revert "don't update configmap while diff-run"

This reverts commit 9ecf7ac.

* added missing arguments

pkg/kapp/app/interfaces.go

@@ -22,11 +22,11 @@ type App interface {
 	UsedGKs() (*[]schema.GroupKind, error)
 	UpdateUsedGVsAndGKs([]schema.GroupVersion, []schema.GroupKind) error
 
-	CreateOrUpdate(map[string]string) error
+	CreateOrUpdate(map[string]string, bool) error
 	Exists() (bool, string, error)
 	Delete() error
 	Rename(string, string) error
-	RenamePrevApp(string, map[string]string) error
+	RenamePrevApp(string, map[string]string, bool) error
 
 	// Sorted as first is oldest
 	Changes() ([]Change, error)

pkg/kapp/app/labeled_app.go

@@ -44,8 +44,8 @@ func (a *LabeledApp) UsedGVs() ([]schema.GroupVersion, error)
 func (a *LabeledApp) UsedGKs() (*[]schema.GroupKind, error)                               { return nil, nil }
 func (a *LabeledApp) UpdateUsedGVsAndGKs([]schema.GroupVersion, []schema.GroupKind) error { return nil }
 
-func (a *LabeledApp) CreateOrUpdate(labels map[string]string) error { return nil }
-func (a *LabeledApp) Exists() (bool, string, error)                 { return true, "", nil }
+func (a *LabeledApp) CreateOrUpdate(labels map[string]string, isDiffRun bool) error { return nil }
+func (a *LabeledApp) Exists() (bool, string, error)                                 { return true, "", nil }
 
 func (a *LabeledApp) Delete() error {
 	labelSelector, err := a.LabelSelector()
@@ -70,7 +70,7 @@ func (a *LabeledApp) Delete() error {
 }
 
 func (a *LabeledApp) Rename(_ string, _ string) error { return fmt.Errorf("Not supported") }
-func (a *LabeledApp) RenamePrevApp(_ string, _ map[string]string) error {
+func (a *LabeledApp) RenamePrevApp(_ string, _ map[string]string, _ bool) error {
 	return fmt.Errorf("Not supported")
 }
 

pkg/kapp/app/recorded_app.go

@@ -127,7 +127,7 @@ func (a *RecordedApp) UpdateUsedGVsAndGKs(gvs []schema.GroupVersion, gks []schem
 	})
 }
 
-func (a *RecordedApp) CreateOrUpdate(labels map[string]string) error {
+func (a *RecordedApp) CreateOrUpdate(labels map[string]string, isDiffRun bool) error {
 	defer a.logger.DebugFunc("CreateOrUpdate").Finish()
 
 	app, foundMigratedApp, err := a.find(a.fqName())
@@ -152,7 +152,7 @@ func (a *RecordedApp) CreateOrUpdate(labels map[string]string) error {
 		return a.updateApp(app, labels)
 	}
 
-	return a.create(labels)
+	return a.create(labels, isDiffRun)
 }
 
 func (a *RecordedApp) find(name string) (*corev1.ConfigMap, bool, error) {
@@ -166,7 +166,7 @@ func (a *RecordedApp) find(name string) (*corev1.ConfigMap, bool, error) {
 	return cm, true, nil
 }
 
-func (a *RecordedApp) create(labels map[string]string) error {
+func (a *RecordedApp) create(labels map[string]string, isDiffRun bool) error {
 	configMap := &corev1.ConfigMap{
 		ObjectMeta: metav1.ObjectMeta{
 			Name:      a.name,
@@ -197,7 +197,13 @@ func (a *RecordedApp) create(labels map[string]string) error {
 		return err
 	}
 
-	_, err = a.coreClient.CoreV1().ConfigMaps(a.nsName).Create(context.TODO(), configMap, metav1.CreateOptions{})
+	createOpts := metav1.CreateOptions{}
+	if isDiffRun {
+		createOpts.DryRun = []string{metav1.DryRunAll}
+	}
+	app, err := a.coreClient.CoreV1().ConfigMaps(a.nsName).Create(context.TODO(), configMap, createOpts)
+
+	a.setMeta(*app)
 
 	return err
 }
@@ -216,7 +222,7 @@ func (a *RecordedApp) updateApp(existingConfigMap *corev1.ConfigMap, labels map[
 	return nil
 }
 
-func (a *RecordedApp) RenamePrevApp(prevAppName string, labels map[string]string) error {
+func (a *RecordedApp) RenamePrevApp(prevAppName string, labels map[string]string, isDiffRun bool) error {
 	defer a.logger.DebugFunc("RenamePrevApp").Finish()
 
 	app, foundMigratedApp, err := a.find(a.fqName())
@@ -263,7 +269,7 @@ func (a *RecordedApp) RenamePrevApp(prevAppName string, labels map[string]string
 		return a.renameConfigMap(app, a.name, a.nsName)
 	}
 
-	return a.create(labels)
+	return a.create(labels, isDiffRun)
 }
 
 func (a *RecordedApp) migrate(c *corev1.ConfigMap, labels map[string]string, newName string) error {

pkg/kapp/cmd/app/deploy.go

@@ -99,9 +99,9 @@ func (o *DeployOptions) Run() error {
 	}
 
 	if o.PrevAppFlags.PrevAppName != "" {
-		err = app.RenamePrevApp(o.PrevAppFlags.PrevAppName, appLabels)
+		err = app.RenamePrevApp(o.PrevAppFlags.PrevAppName, appLabels, o.DiffFlags.Run)
 	} else {
-		err = app.CreateOrUpdate(appLabels)
+		err = app.CreateOrUpdate(appLabels, o.DiffFlags.Run)
 	}
 
 	if err != nil {

test/e2e/diff_test.go

@@ -375,3 +375,30 @@ data:
 
 	require.Containsf(t, out, expectedOutput, "Did not find expected diff output")
 }
+
+func TestDiffRun(t *testing.T) {
+	env := BuildEnv(t)
+	kapp := Kapp{t, env.Namespace, env.KappBinaryPath, Logger{}}
+	kubectl := Kubectl{t, env.Namespace, Logger{}}
+
+	name := "not-create-configmap-diff-run"
+	cleanUp := func() {
+		kapp.Run([]string{"delete", "-a", name})
+	}
+
+	cleanUp()
+	defer cleanUp()
+
+	yaml1 := `
+apiVersion: v1
+kind: ConfigMap
+metadata:
+  name: config
+`
+
+	_, _ = kapp.RunWithOpts([]string{"deploy", "-f", "-", "-a", name,
+		"--diff-run"},
+		RunOpts{IntoNs: true, AllowError: true, StdinReader: strings.NewReader(yaml1)})
+
+	NewMissingClusterResource(t, "configmap", name, env.Namespace, kubectl)
+}